Perceived stress, low back pain, and work ability

Introduction
Low back pain (LBP) is an important cost factor due to its impact on work ability and productivity. With decreasing physical workload and increasing psychological demands in a modern working society, the risk profile of LBP is changing. The objective of this study was to clarify the prevalence of LBP in employees and its dependence on job level (professional and managerial staff, skilled workers, and frontline operators), the interrelation with perceived stress and to investigate the impact of LBP on work ability.

Methods
We examined 867 employees from one division in BASF Ludwigshafen, 653 of which returned complete questionnaires. LBP and stress perception were assessed using standardized questionnaires. The questions directed at LBP included past and current LBP, duration and frequency of LBP-related handicap in both private and occupational lives, and need for medical consultation. The questions directed at job stress perception included safety at the workplace, self-rated health status, frequency of stress symptoms, job demands, time pressure and impaired work life balance. The outcome of interest was self-estimated health measured with Work Ability Index (WAI).

Results
Lifetime prevalence of LBP among participants was about 70%, independent of job level. There were significant differences in “handicap in job” and “duration of handicap” across different job levels. Regarding the association with LBP, duration of handicap turned out to be the strongest predictor for deteriorating WAI, followed by age and BMI. However, in the full model several stress parameters remained as independent influence factors on WAI.

Discussion
Perceived occupational stress had an apparent impact on LBP, and persistent LBP predicted worsening WAI. Apart from this sequential relation, both factors exert significant independent influences on WAI. Consequently, interventions to reduce the impact of LBP on employees’ health as well as productivity have to target both physical and psychological dimensions.